Perovskite oxide composites for bifunctional oxygen electrocatalytic activity and zinc-air battery application- a mini-review

Zinc-air batteries (ZABs) are considered as a potential alternative to next-generation batteries. However, the slow reaction kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), involved in the charging and discharging of ZAB hinder their real-world applicability. Thus, developing an excellent bifunctional OER/ORR electrocatalyst that exhibits solid cyclic stability is crucial. Perovskite oxides are known for their composition and structural flexibility, which allows for the modulation of the electronic structure of electrocatalysts by incorporating foreign metals into oxides, resulting in improved oxygen electrocatalytic activity. Achieving bifunctional oxygen electrocatalytic activity through a single pristine perovskite oxide is challenging due to the requirement of different reaction steps. Building heterostructures by combing perovskite oxides with metal, metal alloys, metal hydroxides, metal oxides, spinel oxides, and N-doped carbon materials enhances the active sites of the catalyst for bifunctional activity and ZAB application. In this review, we discuss the mechanism involved in ZAB and bifunctional oxygen electrocatalytic activity, mainly focusing on perovskite oxide heterostructure synthesizing strategies and their performance in ZAB. This review aims to pave the way for designing inexpensive perovskite oxide-based electrocatalysts and tailoring the active sites for improved energy conversion and industrialization.